diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -5343,7 +5343,7 @@ static PyMethodDef _decimal_methods [] =
 
 static struct PyModuleDef _decimal_module = {
     PyModuleDef_HEAD_INIT,
-    "decimal",
+    "_decimal",
     doc__decimal,
     -1,
     _decimal_methods,
diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -574,7 +574,7 @@ static PyMethodDef module_methods[] = {
 
 struct PyModuleDef _PyIO_Module = {
     PyModuleDef_HEAD_INIT,
-    "io",
+    "_io",
     module_doc,
     sizeof(_PyIO_State),
     module_methods,
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -2731,6 +2731,13 @@ PyInit__testcapi(void)
     m = PyModule_Create(&_testcapimodule);
     if (m == NULL)
         return NULL;
+    /* Import ourselves recursively and look up an attribute */
+    if (PyRun_SimpleString("import _testcapi; _testcapi.test_list_api")) {
+        PyErr_SetString(PyExc_RuntimeError,
+                        "_testcapi recursive import failed");
+        Py_DECREF(m);
+        return NULL;
+    }
 
     Py_TYPE(&_HashInheritanceTester_Type)=&PyType_Type;
 
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -110,8 +110,10 @@ PyModule_Create2(struct PyModuleDef* mod
             _Py_PackageContext = NULL;
         }
     }
-    if ((m = (PyModuleObject*)PyModule_New(name)) == NULL)
+    if ((m = (PyModuleObject *) PyImport_AddModule(name)) == NULL)
         return NULL;
+    assert(PyModule_Check(m));
+    Py_INCREF(m);
 
     if (module->m_size > 0) {
         m->md_state = PyMem_MALLOC(module->m_size);